A brush is the most common form of coating applicator used by amateurs and professionals to paint objects, walls and the like. A number of attempts have been made to improve on the simple applicator facilitating the use thereof and improve on the application of the coating to the object. One aim is to provide a surface finish on the applied coating that is smooth with complete coverage simulating what might be attained by way of a spray system. Spray systems, however, are expensive and therefore not available to everyone and furthermore not all jobs are suited to paint spraying, for example, the interior walls of a house.
Improvements of hand-use applicators for coatings include paint pads, paint rollers and the like but the most common coating applicator still is the paint brush. Paint brushes can be relatively cheap or relatively costly and there is some correlation between the cost of the paint brush and the quality of use and coating applied. Paint brushes, particularly cheap ones, have annoying traits that include (1) loss of fibres during painting that mar the finish and require messy removal and rework; (2) dripping and running of the coating material down the handle leading to a messy situation and additional clean up time and effort; and (3) drying of the coating material at the base of the fibres leading to reduced reservoir capacity. This latter drawback also results in dried particles often breaking off and marring the coating applied.
For the purpose of obtaining a smoother finish on the applied coating foam applicators have been provided but they too have numerous drawbacks which include loss of foam particles during use which mars the surface finish and are next to impossible to remove or detect during application of the coating. Foam applicators also generally are of the type for example illustrated in Ginter's U.S. Pat. No. 3,105,263 issued Oct. 1, 1963, which includes a relatively rigid center piece projecting from the handle into the interior of the applicator. This gives rise to a very stiff applicator making it difficult to use as well as making it difficult to apply an even coating because of being unable to dispense liquid from the reservoir, provided by the sponge, at a uniform rate during use. Sponge applicators also have a tendency to lose their body integrity when holding a supply of liquid.
The basic functions of hand used coating applicators i.e. paint brushes, paint rollers, paint pads, etc. is to act as a temporary reservoir for a small quantity of the coating material to be applied. The reservoir capacity should be large enough to enable a coating to be applied reasonably effectively and cover a reasonable surface area with each charge but should be small enough to ensure that the coating does not dry out too much on the applicator between charges. Another basic function is to provide control so that the coating applied gets only on the desired area. A further function of the applicator is to spread the coating in a thin smooth film. Paint brushes, particularly cheap brushes, have a tendency to leave brush marks and/or loose fibres but they do have relatively good reservoir characteristics.
Applicators use the capillary action of fibres, or sponge as the case may be, to act as a reservoir. The coating material is drawn up into the fine tubes formed between adjacent fibres or into the air bubbles of a sponge (foam material).
The coating in this reservoir is then drawn out by a squeezing action and by contact between the fibres/foam and the object's surface as the applicator is drawn across the object being coated. The spread is determined by the pressure of application and the length and rigidity of the fibre/foam. With fibres of usual length very little pressure is required to cause adjacent fibres to part and spread. This characteristic is of course used to advantage. The amount of pressure varies the spread and consequently the coverage.
The brush is used to control and there should be a clear line of distinction between the coated and uncoated area. The degree of control which can be achieved is again dependent on the pressure applied, the length and rigidity of the fibres and the quality of the brush and the fibres used therein.
The spreading action of the brush attempts to produce a coating which is smooth and of even thickness. However, the area of the brush in contact with the object is not entirely flat and smooth and this fact results in brush marks being left in the coating. The degree of unevenness or the depth of the brush marks is dependent on the fineness or coarseness of the fibres (i.e. the diameter of the fibres or the size of the air bubbles in the case of a foam applicator) and on the viscosity and drying time of the coating material. The larger the fibre or bubble diameters and the more viscous and quicker drying the coating material, then the greater the degree of unevenness or brush marks left in the coating.
With brushes there is a trade-off between reservoir capacity and spreading capability and the available control of the coating application. Where the fibres are longer the reservoir capacity and spreading capacity is greater but the degree of control is lessened because the stiffness of the brush is lessened, other things being equal. In the extreme the brush would become more like a mop and there would be little control over where the coating is applied.
There is a further trade-off in size and density of fibre between the smoothness and evenness of finish and the cost of the brush.
Foam applicators tend to produce a smoother finish than fibre brushes but they also tend not to have the rigidity of fibre brushes and therefore do not provide the degree of control and ease of use provided by fibre brushes. Brushes, both fibre and foam, also have a tendency to accumulate dried coating, especially towards the base of the fibres/foam. This can make the brush difficult or impractical to clean thoroughly and this accumulation can reduce reservoir capacity and ease of use of the brush. This coating of dried material can also result in dried coating particles coming adrift from the brush and marring the finish as much or more than fibres or foam particles which come adrift.
One of the major disadvantages and annoyances of using fibre brushes is fibres which come adrift and are left behind on the object's surface, thereby completely spoiling a fine finish or requiring tricky and messy removal of the loose fibre and resmoothing with the brush. If the loose fibre is not removed before the coating material has started to dry significantly its removal can be very difficult and have a very damaging affect on the appearance of the finish and will probably necessitate a re-sanding and a further coat to achieve desirable results.
The wear capabilities of foam applicators are very limited and after a fairly short period of use they tend to begin falling apart, leading to foam particles coming adrift and causing as many or more problems than fibre loss in fibre brushes.
A further problem which can occur with brushes is that of dripping and of coating material running down the handle. This can lead to the brush handle becoming first slippery, then sticky and in both cases, very messy. This makes the brush difficult and uncomfortable to use. This problem can of course be avoided with care; but this requires a higher level of skill on the user's part and the need for this level skill makes the coating implement less user friendly. Where coatings are being applied above the head or at a high angle to the user, this particular problem can indeed be quite irksome.
Applicant's present invention is particularly limited to coating applicators, for example, paint, varnish and stain where the coating applied is in liquid or equivalent form hardening after application into a durable functional and neat appearing, aesthetically pleasing coating. The term "coating applicator" is used herein to describe applicant's device distinguishing it from known washing, cleaning and scrubbing devices. As will be seen hereinafter the present invention is basically a coating applicator with the reservoir coating applying portion thereof encased in a removable cover in the form of a bag made of suitable material to allow the liquid to be appropriately dispensed and spread during application of the coating to an object.
Applicant is aware of scouring and washing devices that utilize a removable cover and attention is particularly directed to the teachings of Gravis U.S. Pat. No. 2,526,199 issued Oct. 17, 1950; Flynn U.S. Pat. No. 4,945,599 issued Aug. 7, 1990, and Goodloe U.S. Pat. No. 2,140,578 issued Dec. 20, 1938. Of interest is also the teachings of Daley U.S. Pat. No. 3,200,427 issued Aug. 17, 1965 and Santana U.S. Pat. No. 2,485,068 issued Oct. 18, 1949.
While some of these patentees disclose a liquid reservoir in the form of a sponge or the like on the end of a handle and wherein the sponge is covered by a removable bag of cloth fabric none have in any way appreciated the attributes of such combination to the art of painting.